SUBJECTS AND METHODS
Forty healthy subjects who had no previous history of neurological, musculo-skeletal or other medical conditions
that could have affected gait were recruited.
All the subjects understood the purpose of this study and gave their written and informed consent prior to their participation.
The study protocol was approved by the local Institutional Review Board and complied with the ethical principles of the Declaration of Helsinki.
The subjects were first asked to walk along a 10 m walkway at a comfortable pace.
The procedure was repeated at two different gait speeds, performed in a random order, to give three sequences of data for each subject.
The three gait speeds were as follows and were always performed at a self-selected speed: slow speed (SS): a gait somewhat slower than normal walking speed; normal speed (NS): a gait at a normal, comfortable speed; fast speed (FS): a gait somewhat faster than normal walking speed13).
The experimental order of the self-selected gait speeds.
A twelve-camera video-based motion analysis system (Vicon, UK) was used to record joint angles.
Sixteen reflecting markers were placed on specific anatomical landmarks on the hip (ASISs and PSISs) as well as on each mid-thigh (the lower lateral 1/3 of the thigh), knee (lateral epicondyle), mid-tibia (lower 1/3 of the shank and lateral malleolus), and foot (second metatarsal head and heel) for capturing joint motion.
The marker protocol was based on the Plug-in-gait marker set.
The motion capture rate was 120 fps.
Two force plates (Advanced Mechanical Technology Inc., USA) were placed at the centre of the 10 m walkway to measure the gait cycle. Data collected from the force plates were digitized at 500 Hz and low-pass filtered at 1,000 Hz.
The system was capable of measuring separate repeated steps over successive strides for extended trials.
Only trials that included three consecutive clean force platform data and complete data were considered.
The statistical analysis was performed using SPSS ver. 12.0. Demographic data such as age, height and weight were
analyzed by one-way ANOVA.
The values of the different gait speeds were compared using one-way ANOVA and least-squares difference as a post hoc test.
Statistical significance was accepted for values of p